Are You Confident of the Diagnosis?

What you should be alert for in the history

Chancroid should be suspected in any patient who presents with a painful genital ulcer, especially with a congruent sexual history and in the proper epidemiologic setting (more commonly seen in Africa and elsewhere in small focal outbreaks).

Characteristic findings on physical examination

Chancroid begins as a small papule that quickly turns into a pustule and then ulcerates. There is nothing pathognomonic in the dermatologic presentation of chancroid. However, a severely painful and deep genital ulcer associated with suppurative lymphadenopathy is highly suggestive. The ulcer is usually deep with ragged, violaceous borders and the base is covered with a yellow-gray exudate.

In the male, chancroid typically occurs on the corona of the penis (Figure 1). Inguinal adenopathy occurs in about half the cases, most often unilaterally and inguinal bubos have been described. The “groove sign” (a linear fibrotic depression parallel to the inguinal ligament, bordered above and below by enlarged lymph nodes) though more typically associated with lymphogranuloma venereum can also be seen.

Figure 1.

A typical painful ulcer of chancroid on the corona of the penis.

Rarely, the ulcer of chancroid will be transient and the clinical presentation will be that of painful inguinal lymphadenopathy without a genital ulcer. In the HIV positive patient, chancroid can present with multiple genital ulcers and in extragenital sites. Other variable dermatologic presentations include papular, serpiginous and phadegenic (coinfection with fusobacterium) which may cause profound tissue destruction.

Expected results of diagnostic studies

Laboratory diagnosis is typically challenging, as most labs do not have sufficient experience with the organism. Diagnosis is therefore commonly made on clinical grounds alone . A definitive diagnosis can be made by culturing the exudate from the ulcer base or by aspiration and culture of a bubo. Gram stain of the ulcer exudate may show gram-negative coccobacilli in a characteristic “school of fish” appearance.

Special culture medium (for details see reference below by Lautenschlager) need to be used and the laboratory should be made aware that Hemophilus ducreyi is suspected. Polymerase chain reaction testing and indirect immunofluorescence tests for H ducreyi have been used but are not FDA approved and only occasionally commercially available.

Diagnosis confirmation

Because bacteriologic diagnosis is difficult in most sexually-transmitted disease (STD) clinics, the Centers for Disease Control (CDC) has definitions for definite and probable chancroid. Definite chancroid requires isolation of H ducreyi from the lesion. Probable chancroid requires consistent clinical findings along with negative darkfield microscopy for Treponema pallidum, negative serologic tests for syphilis, and negative culture for herpes simplex virus (HSV).

Herpes genitalis, atypical syphilis, and traumatic genital lesions are the main disorders in the differential diagnosis. Herpes simplex can be clinically differentiated from chancroid by the multiple vesicular lesions, recurrence, and by less prominent inguinal lymphadenopathy. Syphilis is usually not painful and, unlike chancroid, the genital ulcer will disappear without treatment. Genital trauma is usually suspected by history and less prominent inguinal lymphadenopathy than seen in chanchroid.

The diagnosis is made even more difficult by the fact that patients with chancroid may be coinfected with herpes genitalis or T pallidum. All patients with suspected chancroid should be tested for other sexually transmitted diseases (HIV, Chlamydia, gonorrhea, syphilis, HSV).

Who is at Risk for Developing this Disease?

In developed parts of the world chancroid has become uncommon, with less than 25 cases being reported annually in the United States over the last several years. In developed countries, chancroid is associated with prostitution and illicit drug use. Chancroid is more common in Africa and Southeast Asia and in other parts of the world where HIV is endemic.

What is the Cause of the Disease?

Etiology

Pathophysiology

The disease is almost always transmitted by sexual contact. Many details about the pathogenesisis of chancroid are unclear. Adherence of H duceyi to epithelial surfaces via pili and a lipooligosaccharide with fibronectin, production of an exotoxin, and host resistance factors all likely play a role. Recent data has reported that herpes simplex type 2 infection may reduce the adherence of H ducreyi. Thus, the increasing incidence of HSV infection may be a factor in the reduction in the number of reported cases of chancroid.

Systemic Implications and Complications

Chancroid rarely has any extragenital or systemic manifestations. Chancroid has been described occurring on the abdomen, fingers, thighs , breasts, and lips. In the patients co-infected with HIV, extragenital sites appear to be more common. A case of chancroid conjunctivitis and a case of chancroid-related erythema nodosum have been reported.

Treatment Options

-Azithromycin 1g PO one dose (One dose of directly observed therapy is preferable in most cases)

Optimal Therapeutic Approach for this Disease

In the United States and in developed countries, directly observed, single-dose therapy with ceftriaxone or azithromycin is advised and rarely associated with treatment failures. In parts of the world such as Africa and Asia, where the disease is much more common, some experts recommend longer therapy with erythromycin with direct observation of treatment regimens.

Single-dose regimens with ciprofloxacin should not be used. Amoxicillin-clavulinic acid should not be used, due to reports of high rates of treatment failure .

Patient Management

Since chancroid is difficult to definitively diagnose, therapy is often empiric. Any patient with a genital ulcer that fails to respond to therapy for syphilis or herpes genitalis should be suspected as having chancroid and treated as such. Similarly, any patient with a genital ulcer with negative serologies for HSV and syphilis should be considered for treatment for chancroid.

In many patients with a genital ulcer on initial presentation, a specific diagnosis cannot be made. In this case, a regimen of acyclovir 400mg three times a day for 7-10 days plus ceftriaxone 250mg IM once will treat HSV, chancroid, and likely syphilis. NB: Ceftriaxone dose and duration in syphilis remain undefined. If syphilis is strongly suspected, intramuscular benzathine penicillin should be used or the ceftriaxone duration should be extended to 7 days.

Patients should be tested for syphilis and HIV at the time of diagnosis and 3 months later.

Unusual Clinical Scenarios to Consider in Patient Management

Chancroid is more common in males. In females, the genital lesions, may occur on the cervix or inside the vagina, making the diagnosis on clinical grounds even more difficult.

Treatment response should be seen in 3-7 days. Any patient who fails to show theraputic response by 1 week should be considered for other genital ulcer diseases. Bubos may be slow to respond to adequate antbiotic therapy therefore recurrent aspiration may be indicated. The use of incision and drainage is controversial. HIV-positive patients may be slower to respond to therapy and reports of increased treatment failures with HIV coinfection.

Any sexual contact should also be treated. CDC recommends any sexual contact 10 days prior to onset of symptoms should be treated empirically.

(A detailed and fascinating article. The investigators were able to obtain 220 healthy volunteers willing to be innoculated with chancroid on their upper deltoids - often on multiple sites - and followed for clinical data.)